Method of coupling pipe



Ot. 12, 1948. E. w. REMBERT METHOD 0F COUPLING PIPE Filed sept. 2o, 1944 r2 sheesfsheet 1 ///////////m ff' 'Tia .4.

ATTORNEY Oct. l2, 1948.

Filed sept. 20, 1944 E. w. REM'BERT METHOD oF coUPLING PIPE MACH/NW6 of' Zfe 2 sheets-sheet 2 due to the thickness ofthe asphalt layer.

Patented oct. 12, 194s STATES PAT ortica 4 Claims.

l The instant invention relates to a pipe coupling adapted for use With many types of pipe, for example, steel or iron pipe, but particularly-applicablev for coupling pipes or pipe sections composed of 'a hardened, compressed', asbestos-cement composition and is a division of my co-pending appli cation, S.N. 458,925, now Patent No. 2,379,990, reissued as Patent No. 22,782, iiled- September 19, 1942.

The principal object oi the invention isv the provision of an improved coupling finding a principal eld of use in sewer systems for the handling of domestic wastes. More particularly, the in-` vention has for an `object the provision of such coupling which may be readily assembledv in the `l5- field with a minimum of equipment and which will be leak-proof 'undervv service conditions'.

Anothery object of the invention is the provision of a coupling and method of assembly which eliminates the necessity oi pouring the joint in the eld.

Another object of the invention is the provision of a coupling including a sleeve having a thin tapered liner of asphalt, or the like, in cooperative sealingv relationship with a tapered pipe end. Heretofore, it has been proposedl to con-r structv joints, particularly joints of theY bell and spigot type, by moulding a, liner within the bell for engagement with Vthe pipe. The moulding operations haver necessarily required the sleevev to have a minimum thickness of 1A; to 3/8" in order that satisfactory distribution of' the material and the elimination of excessive quantities of air could take place.. Such prior proposals have not provided a joint of therequired strength As will be understood,V the strength of a joint of this type isla definite function of the thickness of the asphalt material. A further object of the inventionis the provision of a joint and its constituent parts and the method of making them, employinga tapered sleeve liner of such minimum thickness that' flexibility of the joint is retained, but a very substantial increase in strength over the prior proposals results.

My invention will be more fully understood and further objects and advantages thereof will become apparent when reference is made tothe more detailed description which is to follow and lustrating a completed coupling sleeve;

Fig. 4 is a view, partially in elevation and par-1' tially in section, of an assembled coupling-in accordance With the invention; .l

Fig. 5 is a View, similar 'to' Fig; 4, depictingai modification of the coupling; and' Fig.V 6 is a iiow sheet outlining the. steps em--' ployed in the instant method.

Referring now to the drawings, there isv il-A lustrated in- Fig; 1 a section of pipe or conduit W of indefinite: lengthy to be employed in the manufacture of coupling sleeves for the coupling assemblies later described. Conduit. Hl. maybe made of cast iron, steel, orother conventional material employed for such purposes, but is pref--V erably composed cfa hardened, compressed, as

2o bestosecement composition. The conduit is s'elected to have an inner diameterv somewhat: greatconduit is'` then placed in an oven and baked, say, for 24 hours at: 250 F. to` drive out any containedhaving a, melt point, say,v of the order of 20-to 256' As a .specificl example, unl-led asphalt of' 225' F. melt point hasabeen foundy particularly' suitable. However, it will be understood that other materials may be employed;` for example, other asphalts, coal tar pitches, thermo-plastic resins, and the like.

Sufficientof thethermo-plastic liner material f is introduced into the conduit section to provide a layer oi a maximum thickness. somewhat greaterv than the distance between the inner Walluofthe sleeve and the outer tapered end of a pipe section to be coupled thereby. During rotation Vof the conduit section, the asphalt or other liner material is forced out by centrifugal force to form a uniform thickness layer over the entire inner surface of the conduit section. The layer` ot thermo-plastic material molded by centrifugal' force'has been fou-nd to Ibe substantially free- Thev therIrIo-plasticv material'. may comprise asphalt from air bubbles and the like. After the desired amount of material is introduced, rotation is continued until the asphalt is cooled sufficiently to prevent slumping or flowing. The conduit section defining a plurality of coupling sleeves is illustrated at this stage in Fig. 1, the uniform thickness liner being indicated at l2.

The conduit section, preferably after the liner is completely cooled, is divided, by a saw or the like, on the dotted lines I4 of Fig. l, into a plurality of individual sleeves. The coupling sleeves at this stage of their manufacture are illustrated in Fig. 2 by reference character l5. Each individual sleeve I6, with its internal layer or liner l2, is then placed in a suitable device, say a lathe, and the liner machined to have a minimum, but appreciable, thickness adjacent its ends tapering to a maximum thickness adjacent the center of the sleeve as illustrated in Fig. 3. Preferably the minimum thickness is of the order of 11e to 1A; inch. It will be understood that the inner diameter of the liner adjacent the ends of the sleeve, where the sleeve is of minimum thickness, is preferably slightly less than the outer diameter of the pipe section to be inserted therein. The machining operation is controlled to provide a smooth, uniform, sloping surface free, as far as possible, from pits, grooves, and the like.

Referring now particularly to Fig. 4, a coupling assembly employing a sleeve I6 will be described. In preparation for making 'the assembly, Apipe sections |8 and 20, which are to be coupled ltogether, have their end-s machined to dene tapers 22 and 24, respectively. Iapers 22 and 24 are each preferably of a length substantially equal to onehalf the length of the coupling sleeve and are complementary to lthe tapered portions of the sleeve. Pipe sections I8 and 2D may be made of cast iron, steel, or other such conventional materials, but, similarly as the conduit employed for the sleeves, are preferably composed of a hardcned, compressed, asbestos-cement composition, inasmuch as the invention finds a principal field of use in connection with pipe of this character. A machining operation may be carried out on such asbestos-cement materials, as well as upon iron and steel pipe, to provide a smooth surface for contact with the smooth surface of the liner.

In assembling the coupling, the tapered portions of the pipe sections and of the coupling sleeve liner are primed with a suitable primer, such as an asphalt cut-back with benzol or other solvent, benzol being preferred. The coupling sleeve I 'is then pla-ced over the end of one pipe section and pressed firmly home with a twisting or rotary motion to bring the complementally tapered portions of the pipe section and liner into close sealing engagement. The second pipe section is then placed with its tapered end portion in the coupling sleeve and similarly pressed home with a twisting or rotary motion to likewise bring the -contiguous surface of the lliner and pipe section into close sealing engagement. Upon completion of the above steps and the lapse of suicient time to allow the escape of the solvent from the priming material and for the liner to thoroughly harden, the Coupling is ready for use.

A coupling of the type `described above has been foun-d to be particularly satisfactory in connecting sewer vlines for the handling of domestic wastes and the like, 'inasmuch as it is leak-proof under service conditions and may be readily assembled in the field. Owing to the manner in which the sleeve liner is prepared, namely, by

flowing of material into the rotating sleeve and then, after hardening, machining the liner to exact dimensions, 'it has the desired thinness Kat the sleeve ends, whereby an appreciable flexibility is preserved and a very strong serviceable joint is obtained. Both the pipe sections and the sleeves are prepared at the factory, the field assembly requiring practically no equipment or any great degree of skill. It will be understood that in the shipping :and handling of the coupling sleeves, sufficient care must be employed to prevent damage to the lining of asphalt or other thermo-plastic material.

Referring now to Fig. 4, a somewhat modified form of the invention is disclosed. In this embodiment, sleeve 28 is provided with a tapered liner 3Q on one side only. The liner is preferably formed similarly as above, although in this case each sleeve is individually made and the lining material controlled to extend over the interior surface of only a portion of the sleeve, say onehalf, as shown in Fig. 5. In the machining operation the liner is uniformly tapered to have a minimum thickness at one end, the end adjacent the end of the sleeve, and a maximum thickness at the other end. The sleeve 28 is permanently attached to one pipe section 32 as by an adhesive 34, while at the factory. In assembling the coupling on the job, the other pipe section 36, including a tapered end portion as in the other form, is inserted into the open end of the sleeve with a twisting or rotary motion to bring the adjacent surfaces of the liner and the sleeve into close sealing contact.

Having thus described my invention in rather full detail, it will be understood that these details need not be strictly adhered to, but that various changes and modications will suggest themselves to one skilled in the art, all falling within the scope of the invention as dened by the subjoined claims.

What I claim is:

1. A method of forming a coupling sleeve comprising introducing a molten thermoplastic material within a tubular member, rotating said tubular member to distribute said thermoplastic material in a substantially uniform thickness layer to form a liner, cooling and setting said thermoplastic material, dividing said tubular member into a plurality -of sleeves, and shaping the liner within said sleeves to 4define tapers extending substantially uniformly from a minimum thickness adjacent the ends thereof to a maximum thickness adjacent the center thereof.

2. A method of forming a coupling sleeve comprising introducing a molten asphalt within a tubular member, rotating said tubular member to distribute said asphalt in a substantially uniform thickness layer to form a liner for said tubular member, cooling and setting said asphalt, dividing said tubular member into a plurality of individual sleeves, and machining the liner within said sleeves to define tapers extending from a minimum thickness of the order of als to 1/e inch adjacent the ends of the sleeves to a maximum thickness adjacent the center thereof.

3. A method of forming a coupling sleeve from a section of asbestos-cement ypipe comprising priming the inner surface of said pipe, baking said pipe lto remove moisture therefrom, and partially cooling the same, introducing a molten thermoplastic material within said pipe, and rotating the pipe to distribute the molten thermoplastic material in a substantially uniform thickness layer to form a liner, cooling and setting said molten thermoplastic material, dividing the pipe :into a plurality of tubular sleeves, and machining the V liner Within said sleeves to dene tapers extending substantially uniformly from -a minimum thickness adjacent the ends of the Isleeves -to a maximum thickness adjacent the center thereof.

4. A method of forming a coupling sleeve Icomprising priming the inner surface 4of la tubular sleeve, baking the sleeve -to remove moisture therefrom and partially cooling the same, introducing la molten, :thermoplastic material into the sleeve, rotating the sleeve to distribute the molten, thermoplastic material in a substantially um'- form thickness layer lon the inner Wall of the sleeve to form a liner, cooling and setting the thermoplastic material, 'and machining the liner Within the sleeve to dene a taper extending from a minimum thickness at Ian en-d of the sleeve to a maximum thickness intermediate the ends thereof.

ERNEST WAYNE REMBERT.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS 

